A competing stimulus assessment is used to identify stimuli that are associated with a low level of challenging behavior and a high level of engagement. These stimuli are often used as a treatment component for challenging behavior that is maintained by automatic reinforcement. One limitation of implementing competing stimulus assessments is that they may be time consuming. The purpose of the current study was to evaluate the efficacy and efficiency of a latency-based competing stimulus assessment. During the assessment, a therapist presented potential competing stimuli to the participants and contingent on the first occurrence of challenging behavior, the trial was terminated. The results of a brief treatment evaluation indicated that stimuli that were associated with the longest latency to challenging behavior were more effective in competing with challenging behavior relative to stimuli that were associated with shorter latencies. However, procedural modifications were necessary for one participant. The use of latency-based measures improved the efficiency of conducting a competing stimulus assessment.